/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.iotdb.lsm.manager;

import org.apache.iotdb.lsm.request.IRequest;
import org.apache.iotdb.lsm.wal.IWALRecord;
import org.apache.iotdb.lsm.wal.WALReader;
import org.apache.iotdb.lsm.wal.WALWriter;

import java.io.File;
import java.io.IOException;

/**
 * Manage wal entry writes and reads
 */
public abstract class WALManager {

    private final String walDirPath;

    private File walFile;

    // directly use the wal writer that comes with the lsm framework
    private WALWriter walWriter;

    // directly use the wal reader that comes with the lsm framework
    private WALReader walReader;

    private boolean recover;

    public WALManager(String schemaDirPath) {
        this.walDirPath = schemaDirPath;
    }

    public WALManager(
            String walDirPath,
            String walFileName,
            int walBufferSize,
            IWALRecord walRecord,
            boolean forceEachWrite)
            throws IOException {
        this.walDirPath = walDirPath;
        initFile(walDirPath, walFileName);
        walWriter = new WALWriter(walFile, walBufferSize, forceEachWrite);
        walReader = new WALReader(walFile, walRecord);
        recover = false;
    }

    private void initFile(String walDirPath, String walFileName) throws IOException {
        File schemaDir = new File(walDirPath);
        schemaDir.mkdirs();
        walFile = new File(this.walDirPath, walFileName);
        if (!walFile.exists()) {
            walFile.createNewFile();
        }
    }

    /**
     * handle wal log writes for each request
     *
     * @param request request context
     * @throws IOException
     */
    public abstract void write(IRequest request);

    /**
     * for recover, read a wal record and generate it as a request
     *
     * @return request
     */
    public abstract IRequest read();

    public void close() throws IOException {
        walWriter.close();
        walReader.close();
    }

    public String getSchemaDirPath() {
        return walDirPath;
    }

    public File getWalFile() {
        return walFile;
    }

    public void setWalFile(File walFile) {
        this.walFile = walFile;
    }

    public WALWriter getWalWriter() {
        return walWriter;
    }

    public void setWalWriter(WALWriter walWriter) {
        this.walWriter = walWriter;
    }

    public WALReader getWalReader() {
        return walReader;
    }

    public void setWalReader(WALReader walReader) {
        this.walReader = walReader;
    }

    public boolean isRecover() {
        return recover;
    }

    public void setRecover(boolean recover) {
        this.recover = recover;
    }
}
